Democratic presidential candidate <a gi-track='captionPersonalityLinkClicked' href=/galleries/search?phrase=Hillary+Clinton&family=editorial&specificpeople=76480 ng-click='$event.stopPropagation()'>Hillary Clinton</a> smiles as she visits the Gritz Cafe on February 13, 2016 in Las Vegas, Nevada. Clinton is challenging Sen. Bernie Sanders for the Democratic presidential nomination ahead of Nevada's Feb. 20 Democratic caucus.